Fix fork-exec command, close all file descripter otherwise 0-2. Add commands 'true?', 'false?'.   'true?' command return if variable is exists and non-nil value true.   'false?' command return if variable is not exists or nil value true.
Fix fork-exec command, close all file descripter otherwise 0-2.
Add commands 'true?', 'false?'.
  'true?' command return if variable is exists and non-nil value true.
  'false?' command return if variable is not exists or nil value true.

mitchan0321/perfume,mitchan0321/perfume,mitchan0321/perfume,mitchan0321/perfume,mitchan0321/perfume